File:Official proceedings (1926) (14572097540).jpg

Identifier: officialproceedi26rail (find matches)
Title: Official proceedings
Year: 1901 (1900s)
Authors: Railway Club of Pittsburgh
Subjects: Railway Club of Pittsburgh Railroads
Publisher: Pittsburgh, Pa. : The Club
Contributing Library: Carnegie Library of Pittsburgh
Digitizing Sponsor: Lyrasis Members and Sloan Foundation

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r alteration of a railroad bridge, at leastin this emmtry. Several months earlier the Xeeld ConstructionCompany of Pittsburgh reinforced and double-decked the longHighway bridge over the Susquehanna River at I lavre-de-Grace.using arc welding exclusively for held connections. For new bridge construction, welding permits great economvof material for several reasons. Stringers are made continuous,with consequent saving averaging about 20% in weight ofstringers. Flexural members other than rolled beams, whetheracting as stringers. Moor beams, top lateral crossbeams or maingirders in plate girder spans, require less material if designedfor welded assembly than otherwise, because the best type ofwelded plate girder uses plate material only and has a greatersection modulus than a plate and angle girder of the samevveight and depth. Tension members of trusses are designedwithout deductions for rivet holes, such deductions in riveteddesigns frequentlv amounting to 25%. The small amount of 200
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201 labor required to weld in plaee a light brace provides oppor-tunity to reduce the unsupported lengths of long compressionmembers and therefore to reduce their weights. The largestitem of material saving is the elimination of most of the con-nection material, which amounts to 30% of the total weight ofsteel in many riveted bridges. The lightness of the weldedbridge means smaller dead load stresses than for the rivetedone. and this is in itself an additional basis for weight saving. Fig. 12 shows a welded bridge designed to carry a spur ofthe Boston & Maine Railroad across a canal into the plant ofthe Westinghouse Electric & Mfg. Co. at Chicopee Falls. Mass.The design has been approved by the railroad and proposals forconstruction are expected this week. This is a single trackthrough span with extreme skew, each truss being 135 feet long.The live loading is Coopers E 50. The bridge was first de-signed for riveting, with Coopers E 60 loading, this design re-quiring 140 tons o

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